Various technical standards are used for sending and receiving radio frequency signals, such as Code Division Multiple Access (CDMA), Global System for Mobile Communication (GSM), Enhanced Data for GSM Environment (EDGE), CDMA-2000, Time Division Synchronous Code Division Multiple Access (TDSCDMA), Wideband Code Division Multiple Access (WCDMA), Long Term Evolution (LTE), and Worldwide Interoperability for Microwave Access (WiMAX).
For example, WCDMA is a widely adopted third-generation (3G) air interface standard. WCDMA supports a Frequency Division Duplex (FDD) mode of operation in which uplink communication (e.g., from a mobile device to a base station) and downlink communication (e.g., from a base station to a mobile device) are carried out on two separate 5 MHz channels. WCDMA includes a number of frequency bands, such as Band 1 which covers 1920 MHz-1980 MHz and 2110 MHz-2170 MHz. The frequency range 1920 MHz-1980 MHz is used for uplink transmission, and the frequency range 2110 MHz-2170 MHz is used for downlink transmission.
TDSCDMA is another 3G air interface standard that implements a Time Division Duplex (TDD) mode of operation in which a same channel is used for both uplink and downlink transmission, and a number of timeslots are dynamically assigned for downlink and uplink transmission. TDSCDMA includes a number of frequency bands, such as Band 1 covering 2010 MHz-2025 MHz, and Band 2 covering 1880 MHz-1920 MHz.
Different areas of the world rely on different technical standards for providing radio frequency communication (e.g., cell phones, beepers, computers, etc.). To enable continual operation of consumer devices that use different standards, multi-mode devices may be provided for communication using each of a number of different standards that may be encountered. For example, dual-mode or tri-mode transceivers are available to transmit/receive WCDMA Band 1 signals and TDSCDMA Band 1/2 signals within a single device. However, communication systems constructed based on the dual-mode or tri-mode transceivers usually include multiple power amplifiers, each being designed specifically for a particular frequency band, or an expensive multi-band multi-mode power amplifier. Additionally, the communication system using the dual-mode or tri-mode transceiver usually includes a number of duplexers and filters, each having a particular bandwidth.